1. Field of the Invention
The present invention relates to a thin film magnetic head having at least an inductive magnetic transducer for recording and a method of manufacturing the same. More particularly, the invention relates to a thin film magnetic head having a write shield layer for preventing spread of a magnetic flux emitted from a magnetic pole layer and a method of manufacturing the same.
2. Description of the Related Art
In recent years, improvement in performance of a thin film magnetic head is demanded with improvement in areal density of a magnetic recording medium (hereinbelow, simply called “recording medium”) such as a hard disk. Examples of a known method of recording a thin film magnetic head are a longitudinal recording method in which the orientation of a signal magnetic field is set to an in-plane direction (longitudinal direction) of a recording medium and a perpendicular recording method in which the orientation of a signal magnetic field is set to a direction orthogonal to the face of a recording medium. At present, the longitudinal recording method is widely used. However, when a market trend accompanying improvement in areal density is considered, it is assumed that, in place of the longitudinal recording method, the perpendicular recording method will be regarded as a promising method in future for the following reason. The perpendicular recording method has advantages such that high linear recording density can be assured and a recorded recording medium is not easily influenced by thermal fluctuations.
A thin film magnetic head of the perpendicular recording method has, for example, a thin film coil for generating a magnetic flux, a magnetic pole layer for emitting the magnetic flux generated by the thin film coil toward a recording medium, and a write shield layer (magnetic shield layer) for preventing spread of a magnetic flux emitted from the magnetic pole layer. As a thin film magnetic head of this kind, a thin film magnetic head in which a write shield layer is disposed on a trailing side of the magnetic pole layer (medium outflow side) is known (for example, refer to Japanese Unexamined Patent Application Nos. 05-325137 and 06-236526). Another example of the known methods is a method of disposing a write shield layer so as to surround a magnetic pole layer from three directions of a trailing direction and two side directions which are orthogonal to the trailing direction in order to effectively prevent spread of a magnetic flux (refer to, for example, U.S. Pat. No. 4,656,546). The thin film magnetic heads have an advantage of improved recording density since a recording track width on a recording medium is narrowed on the basis of prevention of spread of a magnetic flux.
To spread a thin film magnetic head of the perpendicular recording method, it is necessary to facilitate the manufacturing process as much as possible in consideration of mass production. Although the conventional thin film magnetic head in which the write shield layer is disposed so as to surround the magnetic pole layer from the three directions of the trailing direction and the two side directions is very excellent from the viewpoint of prevention of spread of a magnetic flux, the head has problems such that the process of manufacturing the thin film magnetic head is difficult and the processing precision in manufacture is insufficient. Consequently, at the time of manufacturing the thin film magnetic head of this kind, it is desired to establish an easy, high-precision manufacturing process.